152 PROCEEDINGS OF THE NATIONAL MUSEUM 



short, black or dark brown, especially noticeable on the edges. Arti- 

 cles 5 to 8 generally the widest, 9 and 10 narrower, and 11 elliptical. 

 Article 3 shorter than succeeding articles. Length usually 0.5 to 0.6 

 of the total length in males, about 0.4 in females. 



Tergites all black to dark brown, except pygidium, which in males 

 may be partly translucent, apically truncate, sinuate, emarginate, or 

 distinctly tridentate, projecting widely laterally and apically over 

 ventral segment 8. Pygidium triangular in female. 5 to 7 have 

 posterolateral pointed lobes. 



Ventral segments all black or dark brown, except for yellowish or 

 pinkish rudimentary luminous organs on 8. These organs are occa- 

 sionally not observable in the larger specimens and are usually absent 

 in the smaller ones and females. In males, segment 8 is somewhat 

 emarginate with a short median point. In the females, this segment 

 is triangular with a deep apical V-shaped notch. 



Legs all black or brown, somewhat compressed. Tibial spurs very 

 small and short, pattern 0-1-1. Claws simple, but may have a basal 

 enlargement. 



There seems to be an error in Solier's measurement of the width of 

 P. binotata (—P. obscura). The size is given as 3 to S l A lines (6.35 

 to 7.4 mm.) long by 3% lines (6.88 mm.) broad, a measurement which 

 hardly seems possible. Even 2% lines (4.77 mm.) would be too broad 

 for any specimens I have seen which could be referred to this species. 

 It seems probable that P. binotata was erected on the basis of an 

 unusually broad specimen of P. obscura. 



Of the remaining species previously described and now listed under 

 P. obscura, P. bardelli and P. bioculata were probably pale or imma- 

 ture specimens of P. obscura: E. Olivier's grouping of them and 

 P. lugubris as synonyms of P. obscura seems justified. 



Pyractonema nigripennis Solier 



Figure 7 



Pyractonema nigripennis Solier, in Gay, Hi^t. Fis. Pol. Chile, vol. 4, Zool., p. 448, 



1849. 

 Pyractonema brevipennis Solier, in Gay, Hist. Fis. Pol. Chile, vol. 4, Zool., p. 451, 



1849. 



Material: 100 males and 30 females. 



Dimensions: Males 14.75 to 19.5 mm. long by 4.0 to 7.0 mm. broad; 

 average 17.0 mm. by 5.7 mm. Females 14.5 to 24.0 mm. long by 

 4.0 to 7.0 mm. broad; average 18.1 by 5.3 mm. 



Pronotum essentially semicircular, a little prolonged apically. 

 Length about 0.67 of width. Median vitta with urn-shaped outline. 



Elytra in males about 0.86 of total length. In females about 0.8. 



Aedeagus as in figure 7. 



